Heney s



(No Model.)

H. s. GRACE & W. A. L. MILLER.

HAND P1501", FOR DENTAL ENGINES.

Patented Aug. 19, 1884.

N. Parana PbulwLilhognphe'. Washington, 0. c.

. Unrrnn STATES PATENT @rrice.

HENRY S. GRAGE AND WILLIAM A. L. MILLER, OFSAN FRANCISCO, GAL.

HAND-PIECE FOR DENTAL ENGINES.

FaPECIPICATIONforming part of Letters Patent No. 303,723, dated August19, 1884.

Application filed March 20, 1884. (No model.)

T aZZ whom, it may concern:

' exact description thereof.

part may be put into operation while the other remains inactive.

Referring to the accompanying drawings for a more complete explanationof our invention, Figure lis a longitudinal section of the handpiece,showing the internal mechanism. Fig. 2 shows the cam and connectedmechanism by which the plugger or drill is operated. Fig. 3 is a view ofthe hammer-head and square hollow shank by which the tension of thespring is regulated, and through which the blows are delivered. Fig. 4isa'view of the device for holding the tool in place. Fig. 5 isa view of adevice for giving a backward stroke. Fig. 6 is an exterior view of thecase, showing the opening through which the spring is regulated, and thesleeve or cover. Fig. 7 is a sectional view of the device for holdingthe leverarm, which produces the backward stroke in place.

A is the outer cylindrical shell'of the handpiece, made long enough tocontain the necessary mechanism. The upper end is fitted with a cap, 13,which screws uponthe part A, and makes an ornamental finish.- Throughthe top of this cap the flexible driving-cable l enters, and isconnected with the stem or spindle D, which extends down to near thelower end of the instrument, passing within a cylinder, E, which slidesloosely within the outer casing, for apurpose to be hereinafterdescribed. The point or tip F is screwed upon the lower end of the shellA, and has a hole made through it, through whichthe plugging or burringtool Gpasses. Near the base of this tip is a fiat plate, H, having ahole, through which the shank of the tool. passes. Each tool has achannel, a, turned in it at the point where it passes through thisplate, and the plate is forced to one side by a spring, I), so that oneside of the opening is pressed into the channel or groove, and the toolis thus kept in place. The barring-tools have the channel or groove madeof a length to allow the edge of the plate to just fit into it, as theyonly revolve, but the plugging-tools have the groove made longer, sothat they may have somelongitudinal movement when the blow is given.

I is a square shank having a hole through it, into which the lowerreduced end of the stem D fits so as to turn loosely. This end of thestem has a square socket, into which the square head of the burring'toolfits, and when the stem is revolved freely it will turn the drill.Around the outside of the square shank I a collar or nut, J, fitsloosely, and its periphery is screw-threaded, so as to fit similarthreads which are cut in the interior-of the cylinder E near its lowerend When the shank I is tur ned around, it will turn the nut or collar Jand cause it to travel up or down in the screw-threads in the cylinderE. A col lar, K, on the upper end of the stem D, by its contact with theinterior flat end of the cap B, prevents the stem from being forcedupward, and an other collar, L, secured lower down and within thecylinder E, receives one end of a spiral spring, M, which extends fromit down to the adj ustablc collar or nut J against which it acts, andthus tends to press it and the cylinder E, downward. The adjustablecollar J, by being moved up or down, increases or decreases the tensionof the spring. As the stem D is rotated by the flexible drivingcable 0,and turning loosely in the shank I, into which it extends, as beforedescribed, it will be seen that the burring-tool G,which fits into asquare socket in its lower end, willbe J rotated by it without anyreciprocating motion.

NVhen it is desired to use the implement as a plugger, by pressing uponthe pin (2 the plate H will be pressed back until the hole through it isin line with the hole through the tip F, and the burringtool may beremoved. The plugging-tool is then introduced, and is held by the plateH in the same manner, but its upper end is flat, and the head N on thelower end of the shank I will rest upon it, the cylinder E and shank(which are united by pins which pass through the sides of the cylinderinto a groove in the head N) are pressed down by the action of thespring M, as before described.

In order to produce a reci )rocating motion of the cylinder E, a cam, O,is loosely fitted to l the stem D, so that the latter revolves looselythrough it. A pin, I, extends inward from the cylinder E, so that itsinner end engages the cam, but no movement is communicated to the cam orcylinder until the collar Q is pressed down by means of a pin, R, whichprojects through aslot in the side of the cap B. This collar is fittedto slide on a feather upon the stem D and constantly revolve with it.The pin R projects into a channel or groove in the periphery of thecollar, so that with out interfering with its rotation it may be used topush it up clear of the cam or down, so that a pin, S, upon the lowerface of the collar will engage the cam and cause it to rotate also. Thisacts upon the pin 1? of the cylinder, and it travels up the inclinedface of the cam until it reaches the highestpoint from which it dropsoff, and the spring M causes the whole cylinder E and shank I, with itshead N, to fall upon the head of the pluggingtool G. This being pressedupon the surface to be acted upon, and the channel in which the plate Hfits to hold it being somewhat longer than the thickness of the plate,the full force of the blow will be transmitted to the surface. The rapidrotation of the stem D and cam give the strokes in a rapid continuousmanner. This action may be stopped at any time by raising the collar Qto disengage its pin S from the cam, so that the latter will cease fromrotating.

When it is desired to produce an upward or backward blow of the plugger,it is done by means of a lever-arm, T, the center of which is fulcrumedto a socket, U, which slips over the tip F, so that the inner end of thelever will stand just beneath the hole which is made through thetip. Thepin, which extends down through the tip, has its lower end notched, sothat the end of the lever fits into the notch, and the blows of thehammer or striker are communicated to the lever, and through it to theplugger. The outer end of the lever has an upwardly-projecting socket,into which pluggers may be inserted, and when the blows are given itwill be seen that the action of the lever will change the direction, sothat they will be given upward and backward. The lower part of the caseA has holes V made in it, and a loose sleeve, WV, turning around theoutside,has similar holes, which may be turned to correspond with theholes V, so that through them the headN may be reached, and by turningit the stem I will act to move the nut J, and regulate the tension ofthe spring M. When the sleeve IV is turned around half-way, the holes Vare covered and protected from dirt.

Having thus described our invention, what we claim as new, and desire tosecure by Letters Patent, is-

1. The exterior casing and interior movablecylinder, the stem D,extending from the upper end, where it is connected with the driv ingmechanism, into the shank I, in which it turns loosely, and having asocket to receive the head of the burring -tool, and the transversely-moving plate H and spring, and the grooved tool passing throughthe plate into the socket in the stem D, substantially as hereindescribed.

2. The stem D, extending down through the cylinder E, turning loosely inthe shank I, and surrounded by a spiral spring which extends between afixed collar upon the stem D and a collar, J, having its peripherythreaded, so that it may be screwed up or down within'the cylinder E, toregulate the tension of the spring, substantially as herein described.

3. The exterior case, interior cylinder, and the stem D, extendingthrough and rotated within the cylinder, as shown, and the cam 0, pin Pfrom the cylinder E, collar Q, and pin S, substantially as hereindescribed.

4. In a dental hand-piece, the exterior casing, the interior cylinderwith the head N, grooved and connected with its lower end so as torotate the square shank I, extending in ward from the head, and the nutJ, fitting loosely over the shank, and having its periplr ery threadedto travel up and down in the screw-threaded interior of the cylinder,substantially as herein described.

5. The exterior easing, A, interior cylinder, E, stem D, to the upperend of which a rotary motion is imparted, the lower end having a socketto receive the burring-tool, and a perforated plate through which thetool passes, with a spring by which it is pressed to one side so as'toengage a groove formed around the tool, substantially as hereindescribed.

6. The exterior casing, A, interior cylinder, E, having the lowerrotating head N, and shank I, upon which a nut, J, fits, while itsperipheryfits screw-threads within the cylinder, and the stem D, withthe cam O, and the fixed collars K and L, together with the spring M,substantially as herein described.

7. The exterior casing, A, interior cylinder, E, with head N, adjustingshank and nut, and spiral spring, together with the rotating stem D,loose cam O, and the collar Q, fitted to a feather upon the stem andmovable, so as to engage or disengage with the cam and cause it torotate, substantially as herein described.

8. The casing A, with interior cylinder, E, and spiral spring, therotary shaft D, with cam by which the cylinder E is drawn back, and astem passing through the point or tip, upon which the head of thecylinder strikes its blow, together with a detachable tip or socket, U,and lever T, with a tool-holder at its outer end, substantially asherein described.

In witness whereof we have hereunto set our hands.

HENRY S. GRACE. WILLIAM A. L. MILLER.

\Vitnesses:

Y J OHN D. GAGNON, J os. MoRRIsoN.

